InboXo

A disposable email inbox that lives in your browser toolbar. Open the popup and you already have an address — no signup, no waiting, no tab switching.

Built on mail.tm. Chrome / Edge / Brave / any Chromium browser (Manifest V3).

What it does

• Instant address. The first time you open the popup, a throwaway mailbox is created and stored. It stays yours across popup closes and browser restarts.
• One-click copy. Click the address to copy it.
• Live inbox. Messages arrive on their own — the popup polls every 6s, and a background alarm keeps an unread count on the toolbar badge while the popup is closed.
• Two ways to read. A compact reader in the popup, or a full-page two-pane inbox for long emails.
• Safe rendering. Message bodies render inside a sandboxed <iframe> with scripts disabled, so email JS never runs and email CSS can't leak into the UI.
• Attachments. Listed with size, downloadable through the extension.
• Burn it. The shuffle button releases the current address and provisions a new one.

Monochrome UI, no gradients, no color.

Install from a release

1. Download the extension zip from the Releases page and unzip it.
2. Open chrome://extensions.
3. Turn on Developer mode (top right).
4. Click Load unpacked and select the unzipped folder.
5. Pin InboXo to the toolbar.

Using it

Action	How
Copy the address	Click the address pill
New address	Shuffle button next to the address
Refresh now	Refresh button above the list
Open full page	Expand icon in the popup header
Open one message full page	Expand icon in the popup's message header
Move through the inbox (full page)	↑ / ↓
Close a message (full page)	Esc

The full page also accepts a deep link: tabs/inbox.html?id=<messageId>.

Read this before you use it

• This is public mail. mail.tm addresses are throwaway and unauthenticated by design — treat every message as readable by anyone who learns the address. Never use it for anything that matters.
• The address is not permanent. mail.tm reclaims idle accounts, and the shuffle button deletes the current one on purpose.
• Remote images load. Emails render in a sandboxed frame with images enabled, so tracking pixels will fire, exactly like a normal mail client.
• Credentials for the generated mailbox live in chrome.storage.local so the session can be restored. Nothing is sent anywhere except api.mail.tm.

Development

pnpm install
pnpm dev      # then load build/chrome-mv3-dev as an unpacked extension
pnpm build    # production build -> build/chrome-mv3-prod
pnpm package  # zip for release   -> build/chrome-mv3-prod.zip

Only chrome-mv3 is tested. Other Plasmo targets (pnpm build --target=firefox-mv2) will build but the badge and popup APIs have not been checked there.

Layout

src/
  api.ts                     typed mail.tm client
  background.ts              alarm poll -> unread badge
  popup.tsx                  400x560 popup
  tabs/inbox.tsx             full-page two-pane inbox
  hooks/use-mailbox.ts       provisioning, polling, read/delete state
  hooks/use-copy.ts          clipboard + toast
  lib/mailbox.ts             storage, token refresh, cross-surface sync
  lib/format.ts              dates, names, sizes
  components/                address card, list, reader, brand, toasts
assets/
  icon-<n>x<n>.svg|.png      per-size monochrome icons (16/32/48/64/128)
  icon.svg|.png              512px master / fallback

Icons are authored as SVG and rasterized to PNG per size; Plasmo only consumes PNGs named icon-<n>x<n>.

Permissions

Permission	Why
storage	remember the mailbox between sessions
alarms	poll for mail while the popup is closed
clipboardWrite	copy the address
https://api.mail.tm/*	the only host the extension talks to

Stack

Plasmo · React 18 · TypeScript · Tailwind CSS · react-hot-toast · mail.tm